The present invention relates in general to cooling of an electronics rack(s) of a data center, including rack-mounted assemblages of individual electronics units, such as rack-mounted computer server units.
The power dissipation of integrated circuit chips, and the modules containing the chips, continues to increase in order to achieve increases in processor performance. This trend poses a cooling challenge at both the module and system level. Increased air flow rates are needed to effectively cool high power modules and to limit the temperature of the air that is exhausted into the data center.
In many large server applications, processors along with their associated electronics (e.g., memory, disk drives, power supplies, etc.) are packaged in removable drawer configurations stacked within a rack or frame. In other cases, the electronics may be in fixed locations within the rack or frame. Typically, the components are cooled by air moving in parallel airflow paths, usually front-to-back, impelled by one or more air moving devices (e.g., fans or blowers). In some cases it may be possible to handle increased power dissipation within a single drawer by providing greater airflow through the use of a more powerful air moving device or by increasing the rotational speed (i.e., RPMs) of an existing air moving device. However, this approach is becoming problematic at the electronic component and at the rack level in the context of a computer installation (e.g., a data center).
For example, the sensible heat load carried by the air exiting the rack is stressing the ability of the room air-conditioning to effectively handle the load. This is especially true for large installations with “server farms” or large banks of computer racks close together. In such installations, liquid cooling (e.g., refrigerant or water-cooling) is an attractive technology to manage the higher heat fluxes of selected high heat flux electronic components within the electronics rack. The liquid coolant absorbs the heat dissipated by the high heat flux components/modules in an efficient manner, with the heat typically being transferred from the liquid coolant to an outside environment, whether air or other liquid coolant.